login
A184607
Half the number of (n+1) X 3 binary arrays with no 2 X 2 subblock sum differing from a horizontal or vertical neighbor subblock sum by more than one.
1
28, 160, 918, 5430, 32042, 188394, 1107926, 6519094, 38356642, 225665454, 1327676850, 7811308282, 45957316482, 270386512686, 1590799536334, 9359355830962, 55065102381718, 323971594861746, 1906063733817962
OFFSET
1,1
COMMENTS
Column 2 of A184614.
LINKS
FORMULA
Empirical: a(n) = 5*a(n-1) + 3*a(n-2) + 10*a(n-3) + 29*a(n-4) - 66*a(n-5) - 20*a(n-6) + 8*a(n-7) - 12*a(n-8) + 8*a(n-9).
Empirical g.f.: 2*x*(14 + 10*x + 17*x^2 + 40*x^3 - 137*x^4 - 39*x^5 + 14*x^6 - 22*x^7 + 16*x^8) / (1 - 5*x - 3*x^2 - 10*x^3 - 29*x^4 + 66*x^5 + 20*x^6 - 8*x^7 + 12*x^8 - 8*x^9). - Colin Barker, Apr 14 2018
EXAMPLE
Some solutions for 4 X 3:
..1..0..1....1..0..1....0..1..0....1..0..1....0..1..0....0..1..1....0..1..1
..1..0..0....1..0..0....0..1..0....1..0..1....0..1..0....1..0..1....1..1..1
..1..0..1....1..1..1....1..0..0....1..1..1....1..1..0....0..1..0....1..1..1
..0..0..1....1..0..0....1..0..1....0..0..1....0..0..0....0..1..0....1..0..1
...
...2..1.......2..1.......2..2.......2..2.......2..2.......2..3.......3..4...
...2..1.......3..2.......2..1.......3..3.......3..2.......2..2.......4..4...
...1..2.......3..2.......2..1.......2..3.......2..1.......2..2.......3..3...
CROSSREFS
Cf. A184614.
Sequence in context: A026910 A172220 A255151 * A215699 A220158 A085377
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 18 2011
STATUS
approved